Biomedical subjects

P L M Jansen

Publications and source records attributed to P L M Jansen.

15 recordsLinked to original sources

PubMed2006

CARD15 in inflammatory bowel disease and Crohn's disease phenotypes: an association study and pooled analysis.

BACKGROUND: Three major polymorphisms of the Caspase-Activation Recruitment Domain containing protein 15 gene have been described to be associated with Crohn's disease. Genotype-phenotype studies reported in literature provide conflicting data on disease localisation and behaviour. We investigated the relation of Caspase-Activation Recruitment Domain containing protein 15 with inflammatory bowel disease and Crohn's disease phenotypic characteristics in a large Dutch cohort and performed a pooled analysis on inflammatory bowel disease patients and Crohn's disease phenotypic characteristics reported in association studies. METHODS: We genotyped 781 cases and 315 controls for the R702W, G908R and 1007fsinsC variants and for six microsatellite markers in and close to Caspase-Activation Recruitment Domain containing protein 15. In the pooled analysis data of 7201 inflammatory bowel disease patients and 3720 controls from 20 studies were included. RESULTS: Association was found for Crohn's disease with R702W and 1007fsinsC, including several disease characteristics, and not for ulcerative colitis. In the pooled analysis all three common Caspase-Activation Recruitment Domain containing protein 15 variants showed strong association with Crohn's disease (p<0.00001; odds ratio varying from 3.0 for single heterozygotes to 14.7 for compound heterozygotes) and not with ulcerative colitis. Phenotype analysis showed association with small bowel involvement, stricturing and penetrating disease. CONCLUSION: Caspase-Activation Recruitment Domain containing protein 15 is associated with Crohn's disease and not with ulcerative colitis. All three common Crohn's disease-associated variants are associated with small bowel involvement, the G908R and 1007fsinsC alleles also being associated with a complicated disease course.

Adolescent↗

PubMed2005

[Improved survival and less hepatocellar carcinoma following the successful treatment of chornic hepatitis B].

Successful therapy of hepatitis B e antigen(HBeAg)-positive chronic hepatitis-B patients with interferon alpha leads to HBeAg-seroconversion. The long-term results show that HBeAg-seroconversion is more than a laboratory parameter. In the long run, therapy-induced HBeAg-seroconversion leads to improved survival and a reduced risk for the development of hepatocellular carcinoma. It is striking that cirrhosis was seen twice as often among the responders to interferon therapy as among the non-responders; this could well be an expression of the degree of inflammation in the liver, which is also higher in responders.

Antiviral Agents↗

PubMed2005

[Nonalcoholic steatohepatitis: diagnosis, pathogenesis, treatment and prognosis].

Nonalcoholic steatohepatitis and chronic viral hepatitis C are the two dominant liver diseases in the Netherlands. Hepatic steatosis is usually innocuous but in twenty percent of patients it develops into steatohepatitis. One-fifth of these patients develop liver cirrhosis and hepatocellular carcinoma can also be a consequence of the disease. Nonalcoholic steatohepatitis is characterized by macrovesicular steatosis, necroinflammation, loss ofhepatocytes and fibrosis. Nonalcoholic steatohepatitis often is associated with type 2 diabetes mellitus, hypertension, dyslipoproteinemia and obesity. Insulin resistance plays a major role in the pathogenesis of this disease. Drugs against insulin resistance can ameliorate nonalcoholic steatohepatitis. Gradual weight loss, a diet including polyunsaturated fatty acids and exercise are other important treatment components of this condition.

Carcinoma, Hepatocellular↗

PubMed2005

Bacterial population analysis of human colon and terminal ileum biopsies with 16S rRNA-based fluorescent probes: commensal bacteria live in suspension and have no direct contact with epithelial cells.

BACKGROUND: The commensal intestinal microflora has important metabolic and perhaps also immune modulatory functions. Evidence has accumulated that the microflora plays a role in the pathogenesis of inflammatory bowel disease. Therefore, there is a growing interest in the intestinal microflora and its interaction with the host. Presumably, this interaction takes place at the mucus layer. In this study, we investigated the microflora that is present at the mucus layer and addressed the following questions. Does a specific mucus-adherent microflora exist? Is there direct contact between commensal bacteria and epithelial cells? METHODS: Snap-frozen biopsies were taken of 5 colon regions and of the terminal ileum in 9 subjects with a normal colon. Fecal samples were also collected. Bacteria were detected in cryosections with fluorescent in situ hybridization (FISH) with 16S ribosomal (r)RNA-targeted probes for all bacteria and specific probes for the major representatives of anaerobic microflora (bifidobacteria, Bacteroides, clostridia, atopobia) and aerobic microflora (Enterobacteriaceae, enterococci, streptococci, lactobacilli). RESULTS: With this sensitive technique, bacteria were only observed at the luminal side of the intestinal mucus layer. Very few microcolonies were present at the mucus layer, and the composition of the bacterial microflora present in the feces was similar to that at the mucus layer of the terminal ileum and colon regions. CONCLUSIONS: We did not observe direct contact between bacteria and epithelial cells. The equal distribution of bacterial species suggests that intestinal commensal bacteria live in suspension in the lumen and that there is no specific mucus-adherent microflora.

Adolescent↗

PubMed2005

Expression of apoptosis related proteins during malignant progression in chronic ulcerative colitis.

BACKGROUND: Chronic ulcerative colitis (CUC) is associated with increased risk of developing colon cancer through a dysplasia (intraepithelial neoplasia)-carcinoma sequence. AIMS: To investigate the expression of apoptosis and inflammatory related proteins in CUC. METHODS: The expression of proteins involved in apoptosis and inflammation (inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), Bcl-xl, Fas, and active caspase 3) was investigated and compared with that seen in sporadic colon carcinoma. RESULTS: COX-2 was negative in the epithelium of all samples. iNOS was clearly present in inflammatory areas in CUC epithelium, weakly expressed in dysplasia, and absent or weakly expressed in tumour cells. Bcl-xl was absent in CUC, increased in dysplasia, and highly expressed in most carcinomas. Fas expression was positive in the surface epithelium of CUC, dysplasia, and most tumour cells. Activated caspase 3 was weakly positive in all samples, indicating limited apoptosis. Compared with CUC associated carcinoma, iNOS was consistently expressed in sporadic colon carcinoma cells, whereas Bcl-xl was almost absent in these tumour cells and Fas was only weakly expressed. Activated caspase 3 was present in normal mucosal samples and some tumour cells. CONCLUSION: Apoptosis related proteins--particularly iNOS, Bcl-xl, and Fas-show a distinct pattern of expression in the CUC to carcinoma sequence, which differs from that seen in sporadic carcinoma, but bears a striking resemblance to that seen during neoplastic progression in Barrett's oesophagus. These results support a causal role for chronic inflammation in cancer development in CUC, and treatment of ulcerative colitis should aim to minimise inflammation.

Adenocarcinoma↗

PubMed2004

Increased incidence of azathioprine-induced pancreatitis in Crohn's disease compared with other diseases.

BACKGROUND: Azathioprine is widely used in Crohn's disease. A major drawback is the occurrence of side-effects, especially acute pancreatitis. Acute pancreatitis is rarely seen when azathioprine is used for other diseases than Crohn's disease. AIM: To survey side-effects of azathioprine after liver or renal transplantation, for systemic lupus erythematosis, Wegener's granulomatosis, autoimmune hepatitis, rheumatoid arthritis, ulcerative colitis or Crohn's disease. METHODS: A computerized search using the term 'azathioprine' or 'imuran' was performed on the Hospital Information System of the university hospital Groningen, resulting in 1564 patients matching our criteria. RESULTS: Eleven of 224 patients with Crohn's disease experienced acute pancreatitis (4.9%) compared with two of 129 (1.5%) with autoimmune hepatitis, two of 388 (0.5%) after renal transplantation, one of 254 (0.4%) after liver transplantation. Acute pancreatitis was more prevalent in Crohn's disease compared with any other disease. Azathioprine-toxicity necessitating withdrawal occurred significantly (P < 0,05) more in rheumatoid arthritis (78 of 317), ulcerative colitis (20 of 94) and Crohn's disease (52 of 224) compared with systemic lupus erythematosis (five of 73), Wegener's granulomatosis (six of 85), autoimmune hepatitis (eight of 129), after liver transplantation (17 of 254) and after renal transplantation (22 of 388). CONCLUSIONS: Acute pancreatitis is strongly associated with Crohn's disease and rarely occurs with other underlying conditions. Overall azathioprine-induced toxicity and the necessity of withdrawal is more common in inflammatory bowel disease and rheumatoid arthritis compared with other diseases.

Acute Disease↗

PubMed2004

Chronic inflammation, apoptosis and (pre-)malignant lesions in the gastro-intestinal tract.

Inflammatory conditions are characterized by activation of the transcription factor nuclear factor kappa B (NF-kappaB), resulting in the expression of NF-kappaB-regulated, inflammation-related genes, such as inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2). Expression of these genes contributes to the survival of cells. Indeed, exposure to pro-inflammatory cytokines in the absence of NF-kappaB activation leads to apoptosis.(1,2) Chronic inflammatory conditions are accompanied by constitutive activation of NF-kappaB and hence, to the continuous expression of pro-survival genes, as has been observed in chronic gastritis.(3) Although beneficial for the survival of cells during exposure to inflammatory stress, the continuous activation of NF-kappaB may also pose a risk: cells with a pro-survival phenotype may give rise to continuously proliferating cells and may thus be tumorigenic. Progression to a malignant phenotype of these cells will most likely involve additional changes in the expression of non-NF-kappaB regulated genes e.g. a shift in the balance of pro- and anti-apoptotic genes towards a more anti-apoptotic phenotype. Literature on inflammation-related genes and the apoptotic balance in pre-malignant and malignant conditions in the gastro-intestinal tract is still scarce and conflicting. In this review, we aim to give an overview of the existing literature and we will focus on inflammation- and apoptosis-related genes in the sequence of normal epithelium-inflamed epithelium-metaplasia-dysplasia-cancer in the gastrointestinal tract, in particular esophagus (Barrett's esophagus: BE), stomach (gastritis) and colon (inflammatory bowel disease: IBD).

Animals↗

PubMed2003

Genetic cholestasis.

Explore the source record for details and available documents.

Cholagogues and Choleretics↗

PubMed2003

IBD and genetics: new developments.

BACKGROUND: Inflammatory bowel disease (IBD) is a complex disorder with an aetiology that is only partly understood. Apart from environmental factors, inheritance contributes to IBD. REVIEW: Family studies show an increased risk among family members of a patient with IBD, particularly among first-degree relatives. In twin studies, concordance for disease type and localization is observed. In genetically isolated groups there is a higher prevalence of IBD. For instance. Ashkenazi Jews carry the highest risk. Further evidence comes from animal species that spontaneously develop IBD. Unlike Mendelian inheritance, in complex genetic diseases like IBD, genes are expected to be low penetrant and therefore less prone to selection, which results in higher expected gene frequencies. NOD2/CARD15, the first gene associated with IBD, is a polymorphic gene involved in the innate immune system. The gene has over 60 variations. Three of these play a role in 27% of patients with CD, with a predilection for patients with ileal disease. CONCLUSION: Genetics plays an important role in unravelling the pathogenesis of IBD leading to possible new therapeutic approaches.

Carrier Proteins↗

PubMed2003

ATP binding cassette transporter gene expression in rat liver progenitor cells.

BACKGROUND AND AIM: Liver regeneration after severe liver damage depends in part on proliferation and differentiation of hepatic progenitor cells (HPCs). Under these conditions they must be able to withstand the toxic milieu of the damaged liver. ATP binding cassette (ABC) transporters are cytoprotective efflux pumps that may contribute to the preservation of these cells. The aim of this study was to determine the ABC transporter phenotype of HPCs. METHODS: HPC activation was studied in rats treated with 2- acetylaminofluorene (2-AAF) followed by partial hepatectomy (PHx). ABC transporter gene expression was determined by real time detection reverse transcription-polymerase chain reaction in isolated HPCs, hepatocytes, cholangiocytes, and cultured progenitor cell-like RLF phi 13 cells and by immunohistochemistry of total liver samples. ABC transporter efflux activity was studied in RLF phi 13 cells by flow cytometry. RESULTS: 2-AAF/PHx treated animals showed increased hepatic mRNA levels of the genes encoding multidrug resistance proteins Mdr1b, Mrp1, and Mrp3. Immunohistochemistry demonstrated expression of Mrp1 and Mrp3 proteins in periportal progenitor cells and of the Mdr1b protein in periportal hepatocytes. Freshly isolated Thy-1 positive cells and cultured RLF phi 13 progenitor cells highly expressed Mrp1 and Mrp3 mRNA while the hepatocyte specific transporters Mdr2, Bsep, Mrp2, and Mrp6 were only minimally expressed. Blocking Mrp activity by MK-571 resulted in accumulation of the Mrp specific substrate carboxyfluorescein in RLF phi 13 cells. CONCLUSION: HPCs express high levels of active Mrp1 and Mrp3. These may have a cytoprotective role in conditions of severe hepatotoxicity.

ATP Binding Cassette Transporter, Subfamily B↗

PubMed2003

Diffuse and intestinal type gastric carcinomas differ in their expression of apoptosis related proteins.

BACKGROUND: Gastric carcinomas can be divided into intestinal and diffuse types, with the last type having a worse prognosis. AIMS: To investigate whether specific patterns in the expression of apoptosis related proteins correlate with carcinoma type and/or prognosis METHODS: The expression of Fas, Bcl-2, Bax, Bcl-xl, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) was studied immunohistochemically and the extent of apoptosis and proliferation was investigated in 11 cases of intestinal type and in eight cases of diffuse type carcinoma. RESULTS: Fas was expressed in all intestinal type and in one diffuse type carcinoma. Bcl-xl was expressed in 10 of 11 intestinal type and in one of eight diffuse type carcinomas. Bcl-2 was expressed in lamina propria immune cells. iNOS was expressed in six of 11 intestinal type and in four of eight diffuse type carcinomas, and COX-2 was expressed in eight of 11 intestinal type and in six of eight diffuse type carcinomas. CONCLUSION: Fas and Bcl-xl expression can differentiate between intestinal type and diffuse type gastric carcinomas. No differences in apoptosis and proliferation between intestinal type and diffuse type gastric carcinomas were observed.

Adenocarcinoma↗

PubMed2002

Expression of apoptosis-related proteins in Barrett's metaplasia-dysplasia-carcinoma sequence: a switch to a more resistant phenotype.

Barrett's esophagus, or columnar-lined esophagus (CLE), is a premalignant disorder in which the stratified squamous epithelium is replaced by metaplastic epithelium. To gain more insight into the process of carcinogenesis in CLE, we studied several factors involved in the apoptotic pathway in biopsies with gastric metaplasia (GM), intestinal metaplasia (IM), dysplasia, and/or adenocarcinoma. Immunohistochemistry was performed for Fas, Bcl-2, Bax, Bcl-xl, inducible nitric oxide synthase (iNOS), and cyclooxygenase 2 (COX-2). Fas staining was positive in the epithelium of all biopsies from patients with CLE but negative in normal gastric mucosa. Fas staining was positive in all tumor cells of the 8 cases containing adenocarcinoma. Bcl-2 was positive in lamina propria immune cells of all specimens. Bax staining was positive in the epithelium of all biopsies, including tumor cells. Bcl-xl was positive in dysplasia and tumor cells, but negative in 8 of 17 biopsies containing IM. iNOS was positive in 20 of 21 biopsies with IM and in 4 of 8 dysplasia biopsies. COX-2 was positive in 7 of 8 adenocarcinomas. We conclude that the apoptotic balance in the transformation from IM to adenocarcinoma switches to an antiapoptotic phenotype because of increased Bcl-xl expression and decreased Bax expression. Fas can be used as a marker for the differentiation of gastric mucosa and metaplasia in the esophagus. iNOS is highly positive in CLE-associated intestinal metaplasia. COX-2 is negative in nonmalignant CLE. Therefore, pharmacologic inhibition of COX-2 activity is unlikely to be effective in the preventing CLE-associated adenocarcinoma. There was no clear correlation between iNOS expression and activation of proapoptotic and antiapoptotic genes.

Adenocarcinoma↗

PubMed2002

Blockade of NF-kappaB activation and donation of nitric oxide: new treatment options in inflammatory bowel disease?

BACKGROUND: Inhibition of NF-kappaB activation has been suggested as an anti-inflammatory treatment strategy in inflammatory bowel disease (IBD). However, NF-kappaB regulated genes like inducible nitric oxide synthase (iNOS) are also involved in cell survival mechanisms. METHODS: Review of the literature on NF-kappaB activation and iNOS induction in IBD. RESULTS: In patients with IBD the mucosal immune response is derailed. The nuclear transcription factor NF-kappaB is a key regulator of the inducible expression of many genes involved in immune and inflammatory responses in the gut. Stimuli like oxidative stress, cytokines (IL-1, IL-6, TNF-alpha), bacteria and viruses can release NF-kappaB from their inactive cytoplasmatic form to the nucleus. Drugs like corticosteroids, sulphasalazine, mesalazine and inhibitory cytokines (e.g. IL-10, IL-11) can prevent the activation of NF-kappaB. New, more potent and selective treatment strategies with anti-sense p65, proteasome inhibitors and viral IkappaBalpha expression vectors aim at the prevention of NF-kappaB activation in mucosal macrophages and T lymphocytes. However, NF-kappaB regulated genes are also involved in survival responses of epithelial cells. For example, inhibition of the NF-kappaB mediated induction of iNOS in epithelial cells could block important anti-apoptotic and anti-microbial survival mechanisms. Nitric oxide may also serve in a negative feedback loop to antagonize prolonged activation of NF-kappaB, thereby limiting chronic inflammation. CONCLUSION: Luminal donation of nitric oxide could block NF-kappaB activation. Selective inhibition of NF-kappaB activation in inflammatory cells could be a treatment option in IBD.

Humans↗

PubMed2002

Increased expression of inducible nitric oxide synthase in circulating monocytes from patients with active inflammatory bowel disease.

BACKGROUND: Inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) synthesis are increased in epithelial cells and in tissue macrophages of the inflamed mucosa from patients with inflammatory bowel disease (IBD). Since tissue macrophages are derived from circulating monocytes, we studied iNOS expression in circulating monocytes and related this expression to disease activity. In view of the possible role of NO in monocyte function, we also studied iNOS expression in relation to markers of monocyte activation. METHODS: The expression of iNOS in circulating monocytes from 15 patients with active IBD, 6 patients who went into remission and 18 healthy controls was quantified by flow cytometry and correlated with surface markers (CD63, CD11b, HLA-DR) for monocyte activation. In addition, iNOS expression in circulating monocytes was assessed by Western blotting, immunocytochemistry and measurement of the NO metabolites nitrite and nitrate in plasma. RESULTS: The expression of iNOS in circulating monocytes and the percentage of iNOS-positive monocytes were increased in patients with active IBD compared to healthy controls (fluorescence index: 1.3 (0.1-6.3) versus 0.8 (0.0-1.8); P < 0.05: percentage of iNOS positive monocytes: 37.3 (1.0-77.0)% versus 5.3 (0.0-43.3)%; P<0.01). The six patients who went into remission all had a marked reduction of iNOS expression. iNOS expression was confirmed by Western blotting and immunocytochemistry. Plasma nitrite and nitrate levels were elevated in three patients with active 1BD. The surface markers for monocyte activation, CD63 and CD11b, were not elevated. HLA-DR expression was decreased on circulating monocytes from patients with active ulcerative colitis. CONCLUSIONS: iNOS is increased in circulating monocytes from patients with active IBD and this increased expression correlates with disease activity. Considering the decreased HLA-DR expression and absence of monocyte activation markers, NO produced by iNOS may have a function in suppressing systemic monocyte activation.

Adult↗

PubMedDate not supplied

Nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is an underdiagnosed liver disease characterised by steatosis, necroinflammation and fibrosis. This disease may eventually develop into cirrhosis and hepatocellular carcinoma. NASH is highly prevalent among obese individuals and among patients with diabetes mellitus type 2. Nonalcoholic fatty liver (NAFL), a precursor of NASH, is the main cause of elevated serum liver enzymes among the general population. Insulin resistance is a major aetiological factor in NASH. Gradual weight loss, physical exercise and drugs that improve insulin sensitivity are potential therapies.

Carcinoma, Hepatocellular↗